LTE is a long term evolution of the technique standard of the Universal Mobile Telecommunications System (UMTS) established by the 3rd Generation Partnership Project (3GPP) organization. The architecture of the LTE wireless networks is more flattened, reducing the system delay and reducing the costs for network building and maintaining. In TDD-LTE, small cells and macro cells are provided. The small cell has a very small volume and can be used indoor and outdoor. Generally, the small cell can cover the indoor space of about 10 m or a range of 2 kilometers in the open air. The small cells are characterized in that they are densely disposed with the coverage ranges mutually crossed. In the scenario of LTE-A heterogeneous networks, the macro cells realize wide area coverage and the small cells realize Hotpoint coverage.
Currently, the dynamic TDD-LTE system has 7 kinds of sub-frame configuration. Different sub-frame configurations provide different uplink to downlink sub-frame ratios according to different uplink and downlink throughputs. However, each small cell base station adjusting the sub-frame structure dynamically according to its requirement for throughput may lead to sub-frame cross interferences between adjacent small cells due to the difference in transmitting directions, as shown in FIG. 1.